Joseph davenpokt



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IMPROVEMENT IN BRIDGE-GIRDERS.

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TO ALL WHOM IT MAY CONOERN:

Beit known that I, JosEPn DavENPoRr, of Massillon,in the county of Stark, and State of Ohio, have invented o. new and useful Form of Girder for Bridges and other structures and I do hereby declare that the following is a full, clear, and exact description of. my invention, reference beingr had to the accompanying.

drawings, Aand to the letters of' reference marked thereon, of which drawings- Figure l is a side View of my girder, one half being shown in full, and the other half in section.

Figure 2 is a'plan of my girder, corresponding to the view shown in iig. 1.

Figure 3 is an enlarged sectional view of a portion of the same girder.

Figure 4 is a view-of section made by `plane :z: y in iig. 3, the other half ot' the arch being restored.

Figure 5 is anl enlarged sectional view of the arch-shoe and its connections.

The nature of my invention consists in the construction of an arch, composed of upper andK lower stringpieces, which are connected together by posts, rods, or bolts, and are kept apart and strengthened by braces', which abut against shoes placed against the arch-string pieces, said shoes being arranged so that connectingposts or bolts pass through them, thus making an arched truss where each part bears such strain as it is best adapted to bear, and the ends ofthe arch,'being connected by a chord or chords, which chord or chords are supported between the ends ofthe arch by suspension-rods, agirder of great strength and stability is formed, and which is suitable for bridge-girders, and any other structure requiring a like form of girder.

To enable others skilled in the art to make and use my invention, I will proceed to describeits construction and operation. v

' The arch is composed of the two string-pieces A and B, the bolts a a, main braces c @counter-braces d d, and shoes L h. The main braces and counter-braces abut squarely against the side faces of the shoes h t, each brace being placed between the face of one shoe and th'eadjoining face 'of the next shoe on the opposite stringpiece. The bolts a a pass through thev string-piece B, then through the shoes L L, and through the string-piece A, being secured by nuts I on the top of the string-piece A.v Through each set of-shoes passtwo o r more bolts a a. The main braces ce are placed in pairs, whilethe counter-braces b pass between'them,'as fully shown in iig. 4. The string-pieces A and B are made of common boiler-plate iron, and the bolts c a are common cylindrical iron bolts. The main braces and counter-braces are hollow cylinders, either of cast or wrought.

iron, and are-easily made by taking extra, heavy gas-pipe and sawing it oi intopieces of the proper length.'`v The shoes it hare of cast iron, and have the pins lele cast en the faces of the shoes, against whichpthe braces bear. These pins Ick are cast about an inch in length, and of a diameter about the same as the inner diameters of .the braces c c and d d, und serve toholdsaid braces in position, the braces being placed over said pins, as fully seen in iig. 3. The arch-shoes E E are ofA castiron, made'as shown.A- The chord C is a continuous piece of plate-iron, lset up edgewise under the arch, the ends being'bent a quarter turn, so as to lie ilat on the bed lot the arch-shoeE. The end of the lower string-piece B is laid on the: end of the chord C, and a bolt, m, or

several bolts m, if desirable, pass through'the bed of the arch-shoe E, the end of the chord C, and the end of the lower string-piece B, thus irmly connecting them together. Ati angle-iron,'F, is bolted on the end of the string-piece B by means ofone or more bolts, f, which pass 'through the bed of the shoe and the ends of the chord and lower string-piece, and to this angle-iron F thel upper string-piece A is bolted by means of the bolt' e, the end of said upper .string-piece abutting against theback of the arch-shoe E. Thisl arrangement of the arch-shoe and its several connections, whereby lthe ends of the arch and chord arermly connected, is fullytp shown in fig. 5. The suspension-rods D D are bolted through the lower sning-p'iec'e-B, or through both stringpieces if desirable,- and are secured by nuts n, ,as shown in fig. 1. The lower ends of these suspension-rods D are bolted to the chord G by means of the bolts o o, which pass' through the chord and ends of suspension-rods.

The modeV of constructing the arch is very simple. The proper -distance between the holes for the boltshb la, andthe 'various bolts e e, m m, and ff, and suspension-rods D D, in the string-pieces .A and B, being calculated .and marked on said plates, the plates are run under the punch, and the holes punched.' The length of one of ,the braces being calculated, they are all cut off toythat length, being all of thesame length. Then, commencing at the centre ofl the arch, two shoes, z k, and the corresponding bolts an, lare put in position. The braces c c and d d, and the next set of sheesh h', with their bolts a a, are put in position, when, on tightening the nuts b b, the necessary camber for the arch is produced. This operation is continued till one half of the arch is completed, when the other part is completed in a similar manner.

It is readily seen that the braces sustain only a compressive strain, to which their form is specially adapted,

while the bolts a a sustain a tensile strain, the shoes 7th a compressive strain, and the string-pieces A and B compressive and tensile strains, so that each part is subjected to the strain to which it is best adapted, and thus a girder of great strength and rigidity is obtained.

-I do not claim as my invention the shoes 71, h, arch-shoes E E, angle-irons F F, suspension-rods D D, chords C, norvany of the bolts taken separately, as all these have been before used; but

What I do claim as my invention, and desire to secure by Letters Patent, is-

1. 'lhe arch, composed of the stringpieccs A and B, shoes it L, tension-boltsa a, main braces c c, and

`counter-braces d d, the several parts being arranged in the manner and for the purposeheren specified.

2. The hollow cylindrical tubes for braces in the construction of a truss, when said braces are so arranged as to take only a compressive strain, an'd cannot be subjected to a tensile strain, substantially as herein shown.

3. The peculiar arrangement and combination of the arch-shoes E, chord C, lower string-piccoli, vangleiron F, bolts m and f, upper string-piece A, and bolts c, the whole being arranged as shown, and for the purpose specified.

As evidence that I claim the foregoing, I have hereunto set my hand, in presence of two witnesses.

JOSEPH DAVENPORT.

Witnesses Fannie TUCKER,

Tu. H. WILLIAMS. 

